Design and setting
We performed a prospective multicentre observational cohort study between August 2013 and July 2018 from 4 tertiary care PICUs in Shanghai. Fifty-two critically ill children were enrolled in this study. The protocol was approved by each institution’s ethics/investigation review board (2016R011-F01).Informed to participation in the study consent was obtained from the guardians of the patients.
Eligibility criteria for this study were as follows: 1) aged between 1 month and 18 years, 2) meet HLH-2004 and MODS diagnostic criteria, 3) treated with HLH-2004 protocol, 4) receiving CRRT during the PICU stay[9]. MODS was defined as the underlying primary disease process leading to at least two organ system dysfuction at any time during PICU stay[10]. Patients with familial history or known genetic predisposition(primary HLH)were excluded from analysis. Data from enrolled patients were entered into standardized electronic case report forms (CRF).